The 49ers rank as one of the NFL’s best defenses against the run in large part because of inside linebackers Patrick Willis and NaVorro Bowman.

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For the second straight year, both were selected All-Pro. In the middle of the Niners’ 3-4 defense, Willis and Bowman are everywhere, plugging gaps, making tackles and moving laterally across the field.

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During the regular season, the two linebackers were a big reason the 49ers were the NFL’s fourth-best team against the run, allowing just 94.2 yards per game. In two playoff games, the 49ers have allowed just 92.5 yards rushing per game.

But when the 49ers face the Ravens in Super Bowl XLVII in New Orleans Feb. 3, Willis and Bowman will be going head-to-head with an opponent as tough, strong and talented as they are: Baltimore fullback Vonta Leach.

Leach, also voted first-team All-Pro just like Willis and Bowman, is a 260-pound battering ram who clears the way for standout running back Ray Rice.

The Ravens love to run the ball, and pride themselves on setting the tone for a game with their physical play. Leach is the man who can make it happen with his crushing blocks. If he can consistently block Willis and Bowman, Rice could not only have a big day on the ground, but it would set up play-action passes for Baltimore quarterback Joe Flacco.

Willis and Bowman know all about Leach, having played against him last season in San Francisco’s 16-6 loss in Baltimore.

“Vonta, he’s an animal,” Willis told USA Today. “He plays the fullback as a true fullback. We had an opportunity to go against him last year. I’ll be honest, you give credit where it’s due and he’s a hard-nosed fullback. There’s no question in my mind that there are going to be times in this game where we’ll have some one-on-ones, and we’ve got to come through. In this kind of game, at this kind of magnitude, it’s all or nothing. We’ll see.”

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Said Bowman: “Leach is good, definitely good. … I think it’s a great matchup. We’ll see who the better man is.”

In last season’s meeting, Willis and Bowman played well and Rice ran for just 59 yards on 21 carries. But as 49ers safety Donte Whitner told USA Today, neutralizing Rice as a runner is one of the keys to a San Francisco victory, and Leach’s blocking is what helps spring Rice.

“We have to take their running game away,” Whitner said. “To do that, we have to be extremely physical with Leach and know where he is. Our linebackers, safeties and outside ‘backers are going to have to make sure we’re physical.”

San Francisco defensive coordinator Vic Fangio is well aware of Leach and his importance.

“He’s dominated some linebackers around the league, inside linebackers in particular,” Fangio told Fox Sports. “And we’d better be ready to take him on.”

So far this postseason, the 49ers linebackers have been outstanding. Not only have Willis and Bowman played well, but so have outside linebackers Ahmad Brooks and Aldon Smith. It was Brooks and Bowman who made plays late in the NFC Championship Game to stop a Falcons drive deep in San Francisco territory.

Fangio is putting his faith in his linebacking corps, a group he truly enjoys coaching.

“They like to be coached,” he told Fox Sports. “They want to play good. They have pride in their performance and they’re a good group.”